Jacob Goldstein

Epicardial High-intensity Focused Ultrasound Cardiac Ablation for Surgical Treatment of Atrial Fibrillation

BACKGROUND The available alternatives to an effective but technically complex Cox maze procedure for surgical treatment of atrial fibrillation include ablation using radiofrequency, microwave, laser, cryotherapy or ultrasound energy sources. The purpose of this study was to evaluate the safety and efficacy profile of high-intensity focused ultrasound cardiac ablation for the surgical treatment of atrial fibrillation. METHODS 14 patients underwent epicardial high-intensity focused ultrasound treatment for atrial fibrillation using the Epicor cardiac ablation system between August 2006 and August 2007. The procedure was performed on the beating heart prior to the commencement of cardiopulmonary bypass for concomitant cardiac procedures. Physical examination, electrocardiography and 24-h Holter monitoring were used to determine the postoperative heart rhythm. RESULTS There were no deaths directly related to the procedure. One patient with myelodysplastic syndrome died of septic complications. Three patients required cardioversion at 1 day, 3- and 4-month intervals postoperatively. The mean follow-up period was 9 months. Currently 10/13 (77%) patients are in sinus rhythm, one patient required insertion of a permanent pacemaker, one patient is in atrial fibrillation and another patient is in atrial flutter. CONCLUSION Epicardial high-intensity focused ultrasound ablation is a viable alternative to the Cox maze procedure for the surgical treatment of atrial fibrillation. It is a safe and efficient procedure that does not require cardiopulmonary bypass and may potentially be performed using less invasive surgical techniques.

Medtronic Mosaic porcine bioprosthesis: Assessment of 12-year performance

BACKGROUND The Mosaic porcine bioprosthesis (Medtronic, Inc, Minneapolis, Minn) was approved in 2000 by the US Food and Drug Administration. Clinical performance was evaluated in 6 centers. METHODS From 1994 to 2000, 797 patients (mean age 69 years) had aortic valve replacement (AVR) and 232 (mean 67 years) had mitral valve replacement (MVR). Concomitant coronary artery bypass grafting was performed with aortic valve replacement (45.4%) and mitral valve replacement (43.5%). Mean follow-ups were 7.5 years for aortic position and 7.3 years for mitral position. RESULTS Early mortalities were 2.8% for AVR and 3.0% for MVR. Late mortalities were 4.2%/patient-year for AVR and 5.1%/patient-year for MVR. Overall 12-year survivals were 55.8% ± 3.7% for AVR and 43.9% ± 7.4% for MVR. Twelve-year freedoms from valve-related mortality were 87.1% ± 3.1% for AVR and 82.5% ± 7.7% for MVR. Twelve-year freedoms from reoperation were 84.0% ± 3.3% for AVR and 82.5% ± 7.5% for MVR. Freedoms from structural valve deterioration (SVD) by explant reoperation at 12 years for AVR were 93.3% ± 2.6% for patients at least 60 years old and 75.9% ± 9.3% for patients younger than 60 years. Freedoms from SVD by explant reoperation at 10 years for MVR were 95.3% ± 7.8% for patients at least 70 years old and 84.0% ± 9.3% for patients younger than 70 years. Hemodynamic performance data at 1 year for AVR (sizes 21-27 mm) were mean systolic gradient range 13.7 ± 4.8 to 10.3 ± 3.2 mm Hg and effective orifice area range 1.5 ± 0.3 to 2.5 ± 0.4 cm(2). For MVR (sizes 25-31 mm), data were mean diastolic gradient range 6.7 ± 1.7 to 3.7 ± 0.9 mm Hg and effective orifice area range 1.9 ± 0.3 to 2.4 ± 0.6 cm(2). CONCLUSIONS Overall performance of Mosaic porcine bioprosthesis to 12 years is satisfactory. Freedoms from SVD by explant reoperation were most satisfactory for aortic position in patients at least 60 years old and mitral position in patients at least 70 years old. Overall actuarial freedom from SVD by explant reoperation is encouraging for patients with MVR.

MANAGING DEEP STERNAL WOUND INFECTIONS WITH VACUUM‐ASSISTED CLOSURE

Deep sternal wound infection is an uncommon but serious complication of cardiac surgery. Currently, there is no consensus on the optimal management. Vacuum‐assisted closure (VAC) has been increasingly used to facilitate wound healing. We aim to review the management of deep sternal wound infections using VAC dressing at our hospital. A retrospective review of consecutive cases of deep sternal wound infections was carried out. Median sternotomies were carried out in 2665 patients between July 2001 and June 2006. Thirty‐one patients developed deep sternal wound infections (1.2%). In 26 of these patients, VAC dressing was used either as a stand‐alone therapy or as an adjunct to late sternal reconstruction. Deep sternal wound infections were diagnosed on average 13 days from initial surgery. Of the patients treated with VAC dressing, 17 (65%) had stand‐alone VAC therapy and 9 had VAC therapy followed by sternal reconstruction. The average duration of VAC dressing in the two groups were 21 and 13 days respectively. There were seven in‐hospital deaths, six in the stand‐alone VAC group and one death from a reconstructive patient who did not have VAC therapy. The length of hospital stay was similar in two VAC groups (37 vs 45 days). Median follow up was 17 months. No late relapse was found in the stand‐alone group. In the intermediate therapy group, two patients had chronic wound sinuses and one patient had a wound collection. Vacuum‐assisted closure dressing may be used both as a stand‐alone and as an intermediate therapy for deep sternal wound infection. Reconstructive surgery may be avoided in a significant proportion of patients. No late relapse has been associated with VAC use.

Stanford Type A Aortic Dissection in Pregnancy: A Diagnostic and Management Challenge

BACKGROUND In women under the age of 40, over 50% of type A aortic dissections occur in the obstetric population. This is a complex situation, with potential catastrophic outcomes for mother and child. Time to diagnosis is often delayed by a low degree of suspicion, atypical presentation and difficulties investigating pregnant women. Management requires early involvement of multiple teams and appreciation of potential complications. We report our experience (the largest series described) and describe our surgical strategy. METHODS A retrospective search of the cardiothoracic surgical database at our centre from 2002 to 2010 identified five pregnant women with type A dissections. RESULTS Median time to diagnosis was 18.5 h (range 5.5-150 h) and median time from diagnosis to arrival in the operating theatre was 1.5 h (range 0.5-54 h). Four patients underwent concomitant Caesarean section and dissection repair. There was one maternal death and one unrelated foetal death. CONCLUSION Occurrence of type A aortic dissection in pregnant women is uncommon but potentially catastrophic. A high index of suspicion and timely investigations are necessary to expedite definitive management. Sound surgical strategies and collaboration with appropriate teams are necessary to optimise outcome.

Giant coronary artery aneurysms in Kawasaki disease--the need for coronary artery bypass.

The incidence of coronary artery involvement has fallen markedly following early gammaglobulin infusions in Kawasaki disease. Nevertheless such involvement may still occur and if giant coronary aneurysms develop they are more likely to lead to myocardial ischaemia. Two subjects are described who developed giant aneurysms, one of whom was subjected to successful coronary artery bypass following the detection of myocardial ischaemia on a nuclear perfusion scan 5 years following his acute episode. The other is being followed to detect the first signs of any ischaemia. While all patients who develop coronary artery aneurysms following Kawasaki disease require diligent long-term review, that is especially important in the few with giant aneurysms. Early detection of significant coronary artery stenosis and its successful treatment may prevent myocardial infarction in childhood and adolescence with all its long-term consequences.

Fatal intraoperative pulmonary thrombosis after graft replacement of an aneurysm of the arch and descending aorta in association with deep hypothermic circulatory arrest and aprotinin therapy

A 69-year-old woman had graft replacement of the distal aortic arch and proximal descending thoracic aorta for a 13 cm atherosclerotic aneurysm. Left ventricular function and coronary artery anatomy were normal, as were results of all preoperative hematologic and coagulation assays. Heparin administration was 300 units/kg plus 5000 units in the pump prime. Kaolin-based activated clotting time (ACT) was kept above 500 seconds during cardiopulmonary bypass (CPB) and above 750 seconds before circulatory arrest. Protamine was reversed on a 1 mg/100 units heparin ratio (Table I). Aprotinin (Trasylol) was given for a total dose of 6 3 10 kallikrein inactivation units (KIU; 2 3 10 KIU intravenously after anesthetic induction, 2 3 10 KIU in the pump prime, and 0.5 3 10 KIU/hr). After establishment of CPB, antegrade and retrograde blood cardioplegic arrest together at 18° C, with continuous retrograde cerebral sanguineous perfusion through the superior vena cava during the period of circulatory arrest, were employed. The aneurysm was resected and replaced with a woven polyethylene terephthalate fiber (Dacron) graft; the arch vessels were reimplanted as a Carrel patch. The patient was weaned from CPB unaided, with normal hemodynamic indexes, effective myocardial contractility, and a dry operative field. Ten minutes later, unheralded right ventricular failure with a normal electrocardiogram occurred. Protamine was discontinued and heparin was readministered to the patient. Despite inotropic support and intraaortic balloon counterpulsation, cardiac function was inadequate. CPB was recommenced, and right ventricular failure frustrated attempts to discontinue CPB. Transesophageal echocardiography revealed no valvular abnormality, with effective biventricular contraction in the decompressed heart. The pulmonary artery was opened, yet no evidence of pulmonary embolism was demonstrable. Right ventricular assistance was commenced. Unexplained intermittent inadequate venous return and raised pulmonary pressures hampered effective right ventricular assistance action, and the patient died 70 minutes later. Postmortem examination revealed extensive deposits of skeinlike, fibrinous material loosely adherent to the walls of the main and segmental pulmonary arteries, right ventricle, and within the venous cannulas. Histologic examination revealed extensive thrombosis within the small pulmonary artery branches. No evidence of thrombosis was detected in other organs. Aprotinin is highly effective in reducing blood loss after cardiac operations. However, safety concerns, initially raised by the Cleveland Clinic group, remain unanswered. The safety of aprotinin in the setting of aortic reconstruction with deep hypothermic circulatory arrest is currently unclear. Sundt and associates from St. Louis and Westaby’s group from Oxford have reported a detrimental effect of aprotinin in this setting of complex aortic operations with deep hypothermic circulatory arrest. The St. Louis group found a higher operative mortality rate, perioperative myocardial infarction rate, and renal failure rate in the aprotinin group than in a historical case-matched control group (15% vs 0%, 20% vs 0%, and 65% vs 5%, respectively). The Oxford group reported a greater incidence of bleeding and thrombosis-related deaths associated with aprotinin. These reports represent large series by experienced

Alkaptonuria-associated aortic stenosis.

Alkaptonuria is an autosomal recessive disorder of tyrosine metabolism, which results in accumulation of unmetabolized homogentisic acid and its oxidized product in various tissues, including the heart. Cardiovascular involvement is a rare but serious complication of the disease. We present two patients who have undergone successful aortic valve replacement for alkaptonuria‐associated aortic stenosis along with a review of the literature. doi: 10.1111/jocs.12129 (J Card Surg 2013;28:417–420)

Orthodox coronary artery bypass surgery: The gold standard in surgical coronary artery disease intervention

Abstract Background: Advances in technology have produced a plethora of means to perform coronary revascularisation either surgically (that is, off pump CABG, Heartport CABG) and/or percutaneously (that is, stenting, rotablation). When comparing the results obtained by these new technologies, too often reference is made to results from the CABG operation of previous eras. Before tried and tested procedures are superseded by new, radical ones, it is essential to establish what the contemporary results of the CABG operation are on an unselected, general patient population. Aim: To examine contemporary results of primary orthodox CABG surgery in an unselected patient population from an Australian teaching hospital. Method: This was a prospective study of all patients having primary CABG surgery from 1 January 1996 to 30 June 1998. Results: 1002 patients had CABG. The mean age was 63.1 years, 33% were aged more than 70 years. Perioperative AMI occurred in 0.2% and CVA in 0.7%. Operative mortality for urgent or elective CABG was 0.4%. At 12 months, freedom from a repeat revascularisation procedure was 97%. Conclusion: Contemporary CABG surgery is associated with a very low morbidity and mortality. This is the gold standard in surgical coronary artery disease intervention and forms the benchmark to which alternative treatment strategies must be compared.

Urgent and emergency coronary artery bypass grafting for acute coronary syndromes.

Background:  Urgent and emergency coronary artery bypass grafting may be associated with significant mortality and morbidity. We report our recent experience with this group of patients.

Pattern of activin A and follistatin release in a sheep model of cardiopulmonary bypass

OBJECTIVE Activin A, a member of transforming growth factor-β superfamily, has been established as a critical cytokine released early in endotoxemia and other inflammatory syndromes. The release of activin A and its binding protein, follistatin during cardiopulmonary bypass (CPB) has not been previously reported. Our study aimed to define the pattern of activin A and follistatin release in a sheep CPB model. METHODS Control group consisted of left thoractomy alone (n=6). CPB was performed using either unfractionated heparin (n=6) or lepirudin (n=6) as anticoagulant. Unlike heparin, lepirudin does not cause activin A and follistatin release on its own. Serum samples were assayed for activin A, follistatin, tumour necrosis factor-α and interleukin-6. RESULTS Compared with the control group, CPB using lepirudin was associated with a biphasic release of activin A. The first peak occurred within the first hour of CPB and a second peak occurred within the early post-operative period, coincident with a large release of follistatin. Close correlation was found between follistatin and IL-6 in the control and lepirudin groups, indicative of a role for follistatin in the acute phase response. In contrast to the control and lepirudin groups, CPB using heparin resulted in a concurrent release of activin A and follistatin. CONCLUSIONS CPB is a trigger for the release of biologically-active free activin A into the circulation, at levels considerably greater than that induced by surgery alone. Triggering release of this critical inflammatory cytokine suggests that activin A may contribute to the adverse outcomes associated with systemic inflammation in cardiac surgery.